The invention relates generally to hydrogen production and processing systems, and more particularly, to enhancement of performance of an integrated hydrogen production and processing system, that may include, but is not limited to, hydrogen purification, compression, and storage sub-systems.
Various types of hydrogen production systems have been designed and are in use. For example, electrolyzer systems generate hydrogen through electrolysis of water. The hydrogen acts as an energy carrier, and can be converted back to electricity for power generation or distributed for use as a fuel. Typically, hydrogen generated from such systems is purified and compressed for storage before it is consumed in an end use system. Many view future hydrogen applications in terms of energy production with hydrogen being produced through electrolysis for direct use in producing power. For example, the end use system may be of a business or industrial nature where the stored hydrogen is used for power generation through hydrogen-powered internal combustion engines, fuel cells, and turbines. Moreover, the stored hydrogen may be distributed to a consumer for powering a vehicle or for use in certain residential applications such as cooking, and so forth.
In certain systems, an alkaline electrolyzer is used for hydrogen generation. Typically, an alkaline electrolyzer uses a liquid alkaline electrolyte such as potassium hydroxide or sodium hydroxide to facilitate electrolysis of water for generation of hydrogen. Further, the liquid electrolyte is required to maintain a desired operating temperature to ensure efficient operation of the electrolyzer. Moreover, during startup operation of the electrolyzer, the electrolyte is required to be heated to increase the temperature of the electrolyte to the desired operating temperature.
In initiation of operation of certain conventional electrolyzers, relatively long time delays are encountered for the electrolyte to reach the desired operating temperature, thereby resulting in long periods of inefficient operation of the electrolyzer at lower temperatures. In certain systems, an external heat source may be employed to heat the electrolyte to reach or maintain a desired operating temperature more quickly. However, adding an external heat source results in loss of overall efficiency of the system due to the addition of energy during this phase of operation. In certain other systems, the electrolyte is gradually heated solely through ohmic losses in the electrolyzer stack. In such systems, the heating of electrolyte results in substantially longer times to reach the desired steady-state temperature, thus reducing the overall efficiency of the system.
Accordingly, there is a need for an integrated hydrogen production and processing system that has enhanced performance achieved through utilizing heat from an internal heat source to heat the electrolyte in the hydrogen production system. It would also be advantageous to provide a hydrogen production and processing system that reduces the time to reach an optimum operating temperature of the electrolyte.